Hippocampal and amygdalar structures preferentially target somatostatin-expressing interneurons in the auditory cortex.

The auditory cortex integrates sensory and contextual inputs in emotion and fear driven situations that can be consolidated over learning. Somatostatin-expressing (SST+) interneurons play a key role in inhibitory modulation of sensory processing, yet their long-range inputs remain poorly characterised. We performed rabies-based retrograde monosynaptic tracing to compare the specific inputs to SST+ interneurons with the general input connectome of neurons in the mouse auditory cortex. Overall, inputs were similar, with the majority of presynaptic neurons originating from the ipsilateral auditory cortex, medial geniculate body and other sensory areas. However, SST+ interneurons received significantly more inputs from limbic regions, including the hippocampus and amygdala, than other auditory neurons. Our results show preferential targeting of SST+ interneurons in auditory cortex by regions involved in emotion and memory. These connections may be involved in auditory learning and state-dependent gating of auditory responses.